Soldering (brazing), or a bonding method relying upon an organic adhesive is known as a method of bonding metallic or ceramic parts together.
A bonding method relying upon an organic adhesive requires costly equipment for maintaining a proper working environment, as it uses an organic solvent, such as toluene. Moreover, it requires costly equipment for the disposal of a contaminated organic solvent.
Soldering does not involve any problem of environment or waste disposal, but requires the heating of a base body and a part to be joined thereto with a solder in a vacuum oven to the melting temperature of the solder (640° C.). The exposure of the base body, etc. to such a high temperature causes its thermal deformation due to a difference in temperature between its surface and interior, or between its upper and lower surfaces. It is usual to apply a high pressure to the base body to suppress its thermal deformation. Thus, soldering brings about a high cost of manufacture, insofar as it requires some measure to be taken to protect the base body, etc. from deformation caused by its heating to a high temperature.